On Mar 2, 2009, at 9:19 AM, Mark H. Wood wrote:
On Fri, Feb 27, 2009 at 08:37:53PM -0500, Robert J. Hansen wrote:
For long-term photographic storage, make a print from photographic
film
on archival-quality print stock. Also, I'm given to understand that
black and white photographs survive the aging process much better
than
color.
Silver chemistry is (or, at least, it used to be) much more resistant
to decay than color dyes. You still have to be sure that the print
has been archivally processed (mainly to wash out all traces of hypo,
which otherwise will continue doing the job it has in the process and
eat away at the silver grains). You still need to keep it away from
atmospheric contaminants when not in use. You can plate the grains
using a bath of gold chloride to protect them a little longer. You
can use vesicular film rather than silver, if you can still find it,
for even longer storage. (Huh, *silver* chemistry is getting harder
to find.)
Used to be that color photos which had to be preserved for a long time
were stored as separation sets: three silver images were made to
capture the three primary colors from the image, to be reassembled
later and reconstitute the color image using the ordinary dye
process. Dunno if it's still done.
I thought it was more or less dead, but then a new company popped up
to do silver YCM separations *generated from a digital scan*.
(Speaking about movies here - obviously anyone can generate
separations for stills with Photoshop or the like). It's less crazy
that it seems on the face of it. The separations have longer life
than a backup tape, and you don't need to remaster separations every
few years. I still think I'd regard such a thing much as I regard the
paper key backups from paperkey: the backup of last resort.
I'd put my trust in a
well-maintained redundant set of digital scans, these days.
Me too. I think most people do, these days. The only issue here is
that every few years, the scanning technology improves to the point
where re-scanning the original (chemical) image becomes worthwhile.
So you do need to keep the original around.
Most photos won't really need all this fancy treatment; you enjoy 'em
while they last, and keep making new ones. The problem is, often we
don't understand which ones *should* have special preservation, until
it's too late.
Indeed. There is an interesting debate over whether digital photos
are too easy to erase. Every now and then, the "unimportant" photo
turns out to be needed. For example: http://digitaljournalist.org/issue9807/editorial.htm
David
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